Platform Advances in RNAi Therapeutics. RNAi Roundtable August 23, 2017

Transcription

1 Platform Advances in RNAi Therapeutics RNAi Roundtable August 23, 2017

2 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 2

3 Reminders Event will run for approximately minutes Q&A Session at end of presentation Submit questions at top of webcast screen Questions may be submitted at any time Replay, slides and transcript available at 3

4 Alnylam Forward Looking Statements This presentation contains forward-looking statements, within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of There are a number of important factors that could cause actual results to differ materially from the results anticipated by these forward looking statements. These important factors include our ability to discover and develop novel drug candidates and delivery approaches and successfully demonstrate the efficacy and safety of our product candidates; pre-clinical and clinical results for our product candidates; actions or advice of regulatory agencies; delays, interruptions or failures in the manufacture and supply of our product candidates; our ability to obtain, maintain and protect intellectual property, enforce our intellectual property rights and defend our patent portfolio; our ability to obtain and maintain regulatory approval, pricing and reimbursement for products; our progress in establishing a commercial and ex-united States infrastructure; competition from others using similar technology and developing products for similar uses; our ability to manage our growth and operating expenses, obtain additional funding to support our business activities and establish and maintain business alliances; the outcome of litigation; and the risk of government investigations; as well as those risks more fully discussed in our most recent quarterly report on Form 10-Q under the caption Risk Factors. If one or more of these factors materialize, or if any underlying assumptions prove incorrect, our actual results, performance or achievements may vary materially from any future results, performance or achievements expressed or implied by these forward-looking statements. All forward-looking statements speak only as of the date of this presentation and, except as required by law, we undertake no obligation to update such statements. 4

5 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 5

6 Alnylam Clinical Development Pipeline Focused in 3 Strategic Therapeutic Areas (STArs): Genetic Medicines Cardio-Metabolic Diseases Hepatic Infectious Diseases Patisiran Fitusiran Hereditary ATTR Amyloidosis Hemophilia and Rare Bleeding Disorders HUMAN POC* EARLY STAGE (IND or CTA Filed-Phase 2) LATE STAGE Inclisiran Hypercholesterolemia (Phase 2-Phase 3) REGISTRATION/ COMMERCIAL COMMERCIAL RIGHTS US, Canada, Western Europe 50% US, Canada, Western Europe Milestones & Royalties Givosiran Acute Hepatic Porphyrias Global ALN-CC5 Complement- Mediated Diseases Global ALN-GO1 Primary Hyperoxaluria Type 1 Subject to partner option rights ALN-TTRsc02 Hereditary ATTR Amyloidosis Subject to partner option rights ALN-HBV Hepatitis B Virus Infection Global 6 *Proof of concept defined as having demonstrated target gene knockdown and/or additional evidence of activity in clinical studies

7 Alnylam Investigational RNAi Therapeutics Platform Extensive Human Safety Experience Number of Programs Number of Clinical Studies Total Patients or Volunteers Dosed Greatest Duration of Exposure >10 >20 >1000 ~36 months Platform related findings* Low incidence (15.2%) of generally mild, transient injection site reactions Low incidence (2.2%) of generally mild, asymptomatic, reversible LFT increases >3x ULN No evidence of safety signals similar to revusiran program Favorable emerging profile for ESC-GalNAc platform compared with competing oligo platforms No evidence of thrombocytopenia, renal toxicity, or systemic inflammatory effects 7 *All reported data as of December 2016 Based on reported study data - not based on direct comparative studies

8 GalNAc-Conjugate Platforms for Delivery to Liver STC-Conjugate ESC-Conjugate ESC+ Conjugate Standard Template Chemistry GalNAc conjugate SC administration Enhanced Stability Chemistry GalNAc conjugate SC administration Enhanced Stability Chemistry GalNAc conjugate, specificity SC administration Revusiran Fitusiran Inclisiran Givosiran ALN-TTRSC02 ALN-GO1 ALN-CC5 ALN-HBV 2018 INDs and CTAs First generation GalNAc conjugate, Initial human POC Second generation GalNAc conjugate, Human POC, greater potency and durability with lower exposures Next generation GalNAc conjugate with further improvements to specificity and therapeutic index 8

9 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 9

10 Enhanced Stabilization Chemistry (ESC) GalNAc-siRNAs SC-Administered Conjugate Platform for Targeted Delivery to Hepatocytes sirna Metabolic stability Intrinsic potency Ligand Trivalent GalNAc High affinity and specificity Asialoglycoprotein Receptor (ASGPR) Highly expressed in hepatocytes High capacity receptor Conserved across species 10

11 Recap of STC to ESC Transition Metabolic profiling of conjugates in mouse liver Region of nuclease hotspots 5 -sense 5 -AS Standard Template Chemistry (STC) Region of nuclease hotspots End stabilization with PS linkages 5 -sense 5 -AS Enhanced Stabilization Chemistry (ESC) = 2 -F = 2 -OMe = Phosphorothioate linkage (PS) 11

12 % Knockdown serum AT (Relative to pre-dose) ESC Significantly Enhances Efficacy and Duration Reduction of AT Protein After Single SC Dose in NHP Potent and durable silencing achieved after single SC dose >10-fold improvement in efficacy over standard template chemistry Substantially extended duration of effect STC-AT3 (10 mg/kg) ESC-AT3 (1 mg/kg) ESC-AT3 (10 mg/kg) Single SC dose Day 12

13 Towards Advanced ESC Designs Iterative Screening Platform to Drive Continuous Design Improvements Objective Identify new generalizable conjugate designs with improved in vivo potency through optimal placement of 2 -F and 2 -OMe modifications Approach Begin with motifs identified by statistical analysis of large dataset of conjugate in vitro activity Apply screening platform using a set of multiple standard sequences (3 targets) and conditions for rapid and systematic evaluation of new designs sirna design In vivo efficacy / exposure In vitro activity Generalizability (expanded screen) 13

14 mrna (norm to PBS) Liver Exposure (ug/g) Performance of Advanced ESC Conjugate in Mice ESC Design Advanced ESC Design 2 -F 2 -OMe PS Target mrna levels in Liver ESC (2.5 mg/kg) Advanced ESC (0.75 mg/kg) 10 1 Total sirna levels in Liver ESC (2.5 mg/kg) Advanced ESC (0.75 mg/kg) h Days Post-Dose h Days Post-Dose 14

15 Performance of Advanced ESC Conjugate in NHP ALN-TTRsc02 (Advanced ESC design) compared to Revusiran Revusiran ALN-TTRsc02 Total Dose Revusiran 45 mg/kg 4154 ALN-TTRsc02 1 mg/kg 8139 Days AUEC for % TTR lowering Adjusting for dose difference (45-fold) and AUEC (1.95-fold), ALN-TTRsc02 shows ~88-fold in vivo potency improvement over Revusiran 15 AUEC= Area under effect curve

16 Mean [+/- SEM] TTR Relative to Baseline ALN-TTRsc02 Phase 1 Preliminary Study Results Single Ascending Dose Study in Healthy Volunteers Days since first dose Cohort Placebo (N=20) TTRSC02 (5mg) (N=6) TTRSC02 (25mg) (N=6) TTRSC02 (Optional; 25mg) (N=6) TTRSC02 (Subjects of Japanese descent; 25mg) (N=6) TTRSC02 (50mg) (N=6) TTRSC02 (Optional; 50mg) (N=6) TTRSC02 (Subjects of Japanese descent; 50mg) (N=6) TTRSC02 (100mg) (N=6) TTRSC02 (200mg) (N=6) TTRSC02 (300mg) (N=6) No SAEs and no discontinuations due to AEs All AEs mild or moderate in severity 14 AEs in 8 subjects considered possibly related to treatment; majority mild Events included injection site erythema, injection site pain, injection site bruising, rhinorrhea, pruritus, cough, nausea, fatigue, genital rash and abdominal pain No clinically significant changes in lab parameters, EKG or physical exam 16 As of data cutoff on 31May2017

17 ED50 (mg/kg) Pushing the Envelope Steadfast Focus on Platform Research Driving Potency Improvements Conjugate potency improvements in mice (single dose ED50) 100 Endolight Endo-light 10 STC STC 1 ESC ESC 0.1 Advanced ESC Advanced ESC Projected Year Sharp s Law 17

18 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 18

19 ALT Elevations in Clinical Programs Data Transfer as of November 2016 STC ESC 19 LNP-siRNA Study Study Population Subjects Treated Max Duration Treatment ALT >3x ULN Patisiran Phase 1 NHV 22 Single dose 0 Patisiran Phase 2 hattr polyneuropathy 29 Up to 4 wks 0 Patisiran Phase 2 OLE hattr polyneuropathy 27^ Up to 25mos 1 GalNAc-siRNA Study Study Population Subjects Treated Max Duration Treatment ALT >3x ULN Revusiran Phase 1 NHV 66 6 wks 1 Revusiran Phase 2 ATTR cardiomyopathy 26 6 wks 1 Revusiran Phase 2 OLE ATTR cardiomyopathy 25^ Up to 18 mos 0 Fitusiran Phase 1, Part A NHV 3 Single dose 0 Severe and moderate HA and HB w/o inhibitor 25 Up to 3 mos 1 Fitusiran Phase 1, Parts B & C Fitusiran Phase 1 D HA and HB w/ inhibitor 16 Up to 3 mos 3 Fitusiran Phase 2 (OLE) HA and HB w/ and w/o inhibitor 23^ Up to 14 mos 3 ALN-CC5 Phase 1, Parts A & B NHV 33 Up to 3 wks 0 ALN-CC5 Phase 1, Part C PNH 6 Up to 6 mos 1 Inclisiran Phase 1 NHV w/ elevated LDL-C 51 Up to 2 mos 1 Inclisiran Phase 2 High Risk CVD; elevated LDL 370 Single dose 1 Givosiran Phase 1, Parts A & B ASHE 23 Up to 2 mos 1 Givosiran Phase 1, Part C AIP 11 Up to 6 mos 1 ALN-AAT Phase 1/2, Parts A & B NHV 19 Up to 4 mos 1 ALN-GO1 Part A NHV 24 Single dose 0 ALT=alanine aminotransferase; ULN=upper limit of normal ^Subjects treated with drug in previous study

20 ALT Elevations in Clinical Programs Data Transfer as of November 2016 LNP-siRNA Study Study Population Subjects Treated Max Duration Treatment ALT >3x ULN Patisiran Phase 1 NHV 22 Single dose 0 Patisiran Phase 2 hattr polyneuropathy 29 Up to 4 wks 0 Patisiran Phase 2 OLE hattr polyneuropathy 27^ Up to 25mos 1 STC ESC GalNAc-siRNA Study Study Population Subjects Treated Max Duration Treatment ALT >3x ULN Revusiran Phase 1 NHV 66 6 wks 1 Revusiran Phase 2 ATTR cardiomyopathy 26 6 wks 1 Revusiran Phase 2 OLE ATTR cardiomyopathy 25^ Up to 18 mos 0 Fitusiran Phase 1, Part A NHV 3 Single dose 0 Frequency Severe and moderate of ALT >3x ULN = 2.2% Fitusiran Phase 1, Parts B & C HA and HB w/o inhibitor 25 Up to 3 mos 1 Fitusiran Phase 1 D HA and HB w/ inhibitor (16/724) 16 Up to 3 mos 3 Fitusiran Phase 2 (OLE) HA and HB w/ and w/o inhibitor 23^ Up to 14 mos 3 ALN-CC5 Phase 1, Parts A & B NHV 33 Up to 3 wks 0 ALN-CC5 Phase 1, Part C PNH 6 Up to 6 mos 1 Inclisiran Phase 1 NHV w/ elevated LDL-C 51 Up to 2 mos 1 Inclisiran Phase 2 High Risk CVD; elevated LDL 370 Single dose 1 Givosiran Phase 1, Parts A & B ASHE 23 Up to 2 mos 1 Givosiran Phase 1, Part C AIP 11 Up to 6 mos 1 ALN-AAT Phase 1/2, Parts A & B NHV 19 Up to 4 mos 1 ALN-GO1 Part A NHV 24 Single dose 0 ALT=alanine aminotransferase; ULN=upper limit of normal ^Subjects treated with drug in previous study 20

21 GalNAc-siRNA Conjugates Wide Therapeutic Index from Non-Clinical GLP Studies NOAEL 1 4 or 7 weeks (mg/kg) NOAEL 13 weeks (mg/kg) Rat NHP Rat NHP NOAEL 6 mos Rat (mg/kg) NOAEL 9 mos NHP (mg/kg) Expected Human Therapeutic Index (TI) 2 Revusiran N/A N/A >80 ALN-TTRsc02 N/A N/A Planned Planned >500 Fitusiran 3, N/A N/A >10 5 Inclisiran >500 ALN-CC >200 Givosiran N/A N/A Ongoing Ongoing >500 ALN-AAT N/A N/A Ongoing Ongoing >500 ALN-HBV N/A N/A Planned Planned >500 Rat Liver Hepatocellular vacuolation: increased number and size of normal rat hepatocellular vacuoles, most contain lipid Increased single cell necrosis Increased mitosis and regeneration Kidney Basophilic granules in proximal tubular 21 epithelium; represents drug accumulation NHP Liver Basophilic granules in Kupffer cells and hepatocytes; represents drug accumulation Lymph nodes Vacuolated macrophages (with basophilic stippling); represents phagocytosis of drug 1 No Adverse Event Level (NOAEL) 2 TI calculated as NOAEL in NHP/Expected dose in man 3 7 week studies 4 NOAEL in hemophilia mice >100 mg/kg, qw x 7 5 Secondary to exaggerated pharmacology

22 Subset of Conjugates Shows Rat Hepatotoxicity at Toxicological Doses and Drop Out of DC Selection Process In silico prediction & In vitro efficacy In vitro screen for predicted off-targets Rodent Knockdown Rat >100x PD dose NHP Knockdown DC Good Actors (60%): No hepatotoxicity Bad Actors (40%): Show hepatotoxicity Single cell necrosis and/or hepatocellular degeneration with LFT 2x upper limit of normal 22

23 Potential Causes of Hepatotoxicity in Rodent Toxicity Studies 1. Non-RNAi drug effects e.g. protein binding RISC loading RISC 2. Competition for RISC loading with mirnas On-target binding Full sequence match mrna Desired on-target activity 3 -UTR Off-target binding Partial sequence match 3. Undesired off-target activity 23

24 n g A S / g liv e r u g A S / g liv e r 5 Modifications on Antisense Strand Can Block RISC Loading With No Impact on Liver Exposure Dose: 30 mg/kg Regimen: q2d x 6 Necropsy: Day 15 RISC loading Sense strand removal Target RNA cleavage mrna R a t R IS C L o a d in g R a t L iv e r E x p o s u r e R IS C lo a d in g b lo c k N o Y e s N o Y e s 1 R IS C lo a d in g b lo c k N o Y e s N o Y e s s ir N A -1 s ir N A -2 s ir N A -1 s ir N A -2 24

25 U /L Blocking Antisense RISC Loading Without Altering 2 F/2 OMe/PS Content Mitigates Hepatotoxicity R a t A L T Dose: 30 mg/kg Regimen: q2d x 6 Necropsy: Day R e fe re n c e ra n g e 0 R IS C lo a d in g b lo c k N o Y e s N o Y e s s ir N A -1 s ir N A -2 RISC loading block (sirna-1) No Yes * ^ * 25 #

26 Accumulation of chemically-modified sirnas in the liver is not sufficient for rat hepatotoxicity. 26

27 u g A S / g liv e r n g A S / g liv e r Changing sirna Chemical Modification Pattern Does Not Reduce Liver Exposure or RISC Loading Dose: 100 mg/kg Regimen: qw x 9 Necropsy: Day 58 ESC Advanced ESC R a t L iv e r E x p o s u r e R a t R IS C L o a d in g E S C Ad v a n c e d E S C 0 E S C Ad v a n c e d E S C 27

28 U /L Changing sirna Chemical Modification Pattern Does Not Mitigate Hepatotoxicity R a t A L T Dose: 100 mg/kg Regimen: qw x 9 Necropsy: Day R e fe re n c e ra n g e 0 ESC S a lin e E S C Ad v a n c e d E S C Advanced ESC # * # * 28

29 sirna sequence, not the chemical modifications, is important for rat hepatotoxicity. 29

30 Potential Causes of Hepatotoxicity in Rodent Toxicity Studies 1. Non-RNAi drug effects e.g. protein binding RISC loading RISC 2. Competition for RISC loading with mirnas On-target binding Full sequence match mrna Desired on-target activity 3 -UTR Off-target binding Partial sequence match 3. Undesired off-target activity 30

31 Relative Target Protein Level Reversir to Abrogate RNAi Activity Without Changing sirna Chemistry or RISC Loading Reversir binds as a synthetic target to antisense strand in functional RISC: Reversir 120% Reversir 100% 80% 60% 40% 20% No Reversir 0% mg/kg GalNAc-siRNA 0.1 mg/kg GalNAc-Reversir Time (Days) 31

32 u g A S / g liv e r n g A S / g liv e r Blocking RISC-Loaded Antisense Strand with Reversir Does Not Reduce Liver Exposure or RISC Loading Prevention Reversir sirna ( ) 3-10 mg/kg 30 mg/kg Treatment Reversir sirna 3-10 mg/kg 30 mg/kg R a t L iv e r E x p o s u r e R a t R IS C L o a d in g Targeting Ctr - Targeting Ctr Targeting Ctr RVR sirna 1 - Targeting Ctr - Targeting Ctr Targeting Ctr RVR sirna 32

33 U /L Treatment U /L Prevention U /L Reversing Activity of RISC-Loaded Antisense Strand Mitigates Hepatotoxicity R a t G L D H Ctr RVR + Targeting RVR 5 0 R eference range Targeting - Targeting Ctr RVR - 1 sirna R a t G L D H * * ^ * * # * * # R eference range 0 - Targeting - Targeting Ctr RVR - 2 sirna # R a t G L D H R eference range Targeting - Targeting Ctr RVR - 3 sirna sirna: 30 mg/kg qw x 3 Reversir: 3 or 10 mg/kg SD Necropsy: Day 15 (Prevention) Day 30 (Treatment)

34 Competition for RISC loading with endogenous mirnas is not a major contributor to rat hepatotoxicity; seed-mediated hybridization of the RISC-loaded antisense strand appears to be important. 34

35 Potential Causes of Hepatotoxicity in Rodent Toxicity Studies RISC loading RISC 2. Competition for RISC loading with mirnas On-target binding Full sequence match mrna Desired on-target activity 3 -UTR Off-target binding Partial sequence match 3. Undesired off-target activity 35

36 Seed-Mediated Off-Target Effects Observed at High Doses RNAseq in Rat Hepatocytes (24 hrs, 10 nm) sirna-1 65 sirna On-target mrna 190 On-target mrna p < 0.05 Downregulated genes Antisense seed enrichment Sense seed enrichment Upregulated genes Antisense seed enrichment Sense seed enrichment sirna-1 p < 2.2e-16 p = p = sirna-2 p < 2.2e-16 p = p = p =

37 ESC GalNAc-siRNA Hepatotoxicity Summary Off-target binding Partial sequence match 3 -UTR Translation repression, mrna destabilization Undesired off-target activity 3 -UTR Antisense strand-driven RNAi-mediated hybridization-based off-target effects, not chemical modifications or competition for RISC loading with mirnas, appear to be important drivers of rat hepatotoxicity. 37

38 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 38

39 ESC+ Strategy for Improved Specificity and Therapeutic Index Utilize seed-pairing destabilization via novel chemical modifications to selectively destabilize off-target binding Off-target binding Partial sequence match pos. 2-8 Antisense loaded RISC Off-target mrna 3 -UTR Undesired offtarget activity 39

40 ESC+ Conjugates Design Considerations Incorporate modification(s) to destabilize seed-pairing Important Considerations 1. On-target potency must be maintained in vivo 2. Minimal impact on metabolic stability 3. Off-target activity should be minimized Position and nature of modification important for all three 40

41 % Target remaining % Target remaining ESC+ vs. ESC Comparable Potency and Reduced Off-Target Activity In Vitro 120 Potency AD IC50: nm Off-Target Activity ESC x Concentration in [nm] AD IC50: nm On-target 100 ESC x Concentration in [nm] On-target

42 Serum TTR relative to Day 0 Serum TTR relative to Day 0 ESC+ vs. ESC Comparable Potency in Rats ESC ESC mg/kg 0.15 mg/kg 0.3 mg/kg 1 mg/kg mg/kg 0.15 mg/kg 0.3 mg/kg 1 mg/kg Day post-dose ED 50 ~ mg/kg Day post-dose ED 50 ~ mg/kg 42

43 ESC+ vs. ESC Hepatotoxicity Mitigated in Rats Dose: 30 mg/kg Regimen: qw x 3 Necropsy: Day 15 ESC ESC+ Degeneration 4/4 (2.5) SCN 4/4, (1.25) Coag Nec 1/4 (1) Increased mitoses 3/4 (2.25) Bile duct hyperplasia 1/4 (1) Vacuolation 4/4 (2) Degeneration 0/4 SCN 1/4, (1) Coag Nec 0/4 Increased mitoses 0/4 Bile duct hyperplasia 0/4 Vacuolation 3/4 (1) 43

44 % K n o c k d o w n T o x g r a d e % K n o c k d o w n T o x g r a d e ESC+ vs. ESC 6-Fold Improvement in Therapeutic Index in Rats ESC A D ESC+ A D E D 8 0 T I = N O A E L E D 8 0 T I N O A E L N O E L N O E L D o s e (m g /k g ) D o s e (m g /k g ) 44

45 ALN-AAT Phase I Single Dose in Healthy Volunteers Serum Transaminases Elevations at 3 and 6 mg/kg SD 8 ALT AST N Placebo X ULN mg/kg mg/kg mg/kg mg/kg mg/kg Data transfer: 30Jun2016 Haslett et al., OTS, September Days Since Dose Days Since Dose 3

46 ALN-AAT02: ESC+ Version of ALN-AAT with Reduced Off-Target Activity In Vitro ALN-AAT ALN-AAT AAT mrna 52 AAT mrna 3-94% RNAseq from Hep3B cells transfected with 10 nm sirna, 16 hrs treatment 46

47 A A T (R e la tiv e to P re -d o s e ) ALN-AAT02 Retains Potent Activity in NHP (1 mg/kg) A L N -A A T A L N -A A T D a y s P o s t-d o s e Plan to advance ESC+ ALN-AAT02 into clinical development in

48 Summary Platform advances continue to drive potency of GalNAc-siRNA conjugates, potentially allowing quarterly or even bi-annual dosing at low doses in humans Demonstrated RNAi-mediated off-target effects as important driver of hepatotoxicity for subset of ESC conjugates in rodent toxicity studies No evidence for impact of chemical modifications on observed toxicity Developed ESC+ design for mitigating seed-mediated off-target effects Improves specificity and further expands therapeutic index of conjugates Plan to advance first ESC+ conjugate, ALN-AAT02, into clinical development in 2018 All future candidates planned to employ ESC+ design 48

49 Agenda Welcome Josh Brodsky, Associate Director, Investor Relations & Corporate Communications Introduction Akshay Vaishnaw, M.D., Ph.D., Executive Vice President of R&D Platform advances in RNAi therapeutics Advanced ESC Design for Potency Improvements Vasant Jadhav, Ph.D., Senior Director, Research Selection of Well Tolerated GalNAc-siRNAs by Screening in Rodent Toxicity Studies Maja Janas, Ph.D., Senior Scientist, Early Development ESC+ Design with Improved Specificity and Therapeutic Index Mark Schlegel, Ph.D., Senior Scientist, Research Q&A Session 49

50 Upcoming RNAi Roundtables Givosiran, in development for the treatment of acute hepatic porphyrias Thursday, September 7, 10:30 am ET Fitusiran, in development for the treatment of hemophilia and rare bleeding disorders Tuesday, September 12, 10:30 am ET Additional details for upcoming RNAi Roundtables, including speakers, dates and times, will be provided on the Capella section of the Company's website, 50

51 Thank you